1. Field of Invention
The present invention relates generally to sensing apparatus embedded in and or applied to gasket structures, and particularly to apparatus applied to exhaust gaskets of internal combustion engines. More specifically, the invention relates to electronic oxygen sensor apparatus provided within structures of exhaust gaskets for measuring oxygen levels in gaseous exhaust media passing through apertures of such gaskets.
2. Description of the Prior Art
It is known to employ electronic sensors in gaskets for sealing between engine components including, for example, the block and cylinder head of a multi-cylinder internal combustion engine. In one case, the gasket comprises a sealing plate having several combustion chamber orifices, with combustion chamber sealing elements situated on the edges of the sealing plate surrounding the combustion chamber orifices. The gasket includes sensor elements for cylinder-specific detection of sealing movements perpendicular to the plane of the sealing plate, caused by pressure changes in respective combustion chambers being measured. All of the sensor elements are arranged outside of the combustion chamber sealing elements, and can be piezoelectric and piezoresistive, as well as glass fiber light guide-style sensors.
In another example, a gasket enclosed sensor system is employed for measurement of combustion chamber parameters and delivery of signals to points external of the engine. The gasket includes a combustion opening substantially surrounding a combustion chamber, and includes an access opening extending from the combustion chamber to a point external of the engine. A metallic sensor terminal is positioned within the access opening, and insulating material substantially surrounds the metallic sensor terminal.
In yet another example, a fluid sensor and associated circuitry are used to indicate presence of oil flow in a multi-cylinder internal combustion engine. The oil sensor includes a heating element positioned within the oil line, directly in the oil flow path. A comparator measures the value of signals from upstream and downstream heat sensors, and triggers a switching circuit when the temperature at the sensors approach one another to indicate an adequate oil flow to the engine.
In still another example, a gasket formed in the shape of an exhaust flange includes a load sensor comprising a pressure sensitive electrically resistive material positioned between electrodes and conductors extending outwardly of the perimeter of the gasket. A seal provided between first and second layers of the gasket, and about the load sensor, provides a seal for the electrodes, which are positioned in a cavity to protect the sensor from fluids.
The present invention provides an electronic oxygen sensor for an automotive exhaust port gasket adapted for insertion between mating surfaces of an engine exhaust port and an exhaust pipe flange for sealing therebetween. The gasket includes at least one primary aperture for accommodating the flow of exhaust gases, and includes at least one electronic oxygen sensor responsive to oxygen levels of the gases passing through said exhaust port. Where a plurality of ports are provided in the gasket, and to the extent that oxygen-sensing is provided at each exhaust port, a real time quality engine management control opportunity based upon cylinder-by-cylinder measurements of said oxygen levels is provided. The specific cylinder-to-cylinder oxygen sensing data can be input into an engine control unit module that includes systems for optimization of engine performance parameters, including fuel economy and emissions levels.
The oxygen sensor is designed to be applied to or embedded within a spacer layer positioned between the beaded or active layers of a multiple-layered steel exhaust port gasket. The oxygen sensor is positioned to be particularly effective to measure changes in oxygen levels of cylinder-specific exhaust gases passing through the primary apertures of the gasket. In this way, a real-time control feedback loop may be established for controlling air-fuel mixtures for optimizing engine combustion parameters, compared to the standard oxygen sensor placement at an exhaust point downstream of the individual exhaust ports.
In the disclosed embodiment, the oxygen sensor system includes a sensing element carried or formed as part of a spacer layer of an exhaust manifold gasket.